Abstract: The injection characteristics of supercritical RP-3 aviation kerosene injected into a quiescent atmospheric environment were studied using schlieren system.The jet generated a barrel shaped wave,Mach disk and reflected shock wave in the downstream of the nozzle exit,with the structure of the jet similar to highly underexpanded air jet.The test results indicate that the axial location of the Mach disk increases with the increasing reduced pressure,however,the reduced temperature almost has little effect on the location of the Mach disk.The mach disk diameter increases with the increasing reduced pressure but decreases with the increasing reduced temperature.The jet length increases with the increasing reduced pressure but decreases with the increasing reduced temperature.